Pneumatic grader.



BATENTED NOV. 17, 1903. W. S. OSBORNE 6: E. O. BRYANT.

PNEUMATIC GRADBR.

{KPPLIOATION FILED JULY 19, 1901..

N0 MODEL.

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UNITED STATES iatented November 17, 1905.

PAT NT OFFICE.

WILLIAM S. OSBORNE AND ELWIN C.v BRYANT, OF ST. LOUIS, MISSOURI.

PN EU MATIQ GRADEF'I.v

SPECIFICATION forming part of Letters Patent No. 744,390, dated November 17, 1903; Application filed July 19, 1901. Serial No. 68,936. (No model.)

To all whom it may concern.-

Be it known that W0,'WILLIAM S. OSBORNE and ELWIN O. BRYANT, citizens of the United States, residing at St. Louis, State of Missouri, have invented certain new and useful Improvements in Pneumatic Graders, of which the following is a full, clear, and exact description, such aswill enable others skilled in the art to which it appertainsto make and use the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 is avertical central sectional elevation on the line 1 1 of Fig. 2; and Figs. 2 and 3 are top plan views, partly in section, taken, respectively, on the lines 2 2 and 3 3 of Fig. 1.

Our present invention relates to pneumatic graders, one of our objects being to provide a simple and cheap construction for effecting the separation or grading of pulverized material or the like.

A further object is to provide an efficient apparatus of the character indicated, in the use of which air is put in motion and passed through the material spread out or scattered in such a manner that the said air mingles with each and every particle of the material, and thus separates the lighter particles and conveys them away, while the heavier particles fall by gravity.

To these ends'and also to improve generally upon apparatus of the character indicated our invention consists in the various matters hereinafter described and claimed.

The present grader is particularly adapted for use in systems for pulverizing and grading materials; but it is capable of and well adapted to use in other. connectionssuch, for example, as cleaning grain.

Referring now more particularly to the drawings, 1 represents a casing which is preferably polygonal (here shown as octagonal) in cross-section, the upper end of said casin g being closed by a cover-plate 2,through which extendsa supply-pipe 3, and the lower portion 4: of the casing being perforated, as shown at 5, and in the form of an inverted truncated pyramid, a central discharge-opening 6 being left at the extreme lower end of said truncated pyramid. About said lower casing portion and suitably spaced therefrom to produce an air-space 7 is an outer casing or shell 8, (preferably in the form of an inverted truncated pyramid,) whose upper edge is substantially at the line formed between the said truncated pyramidal portion of the inner casing and the portion of said casing above the same, a suitable plate 9 closing the space between the upper edge of said outer casing and the said inner casing. At the lower end of said outer casing is a discharge-spout 10, which is preferably provided with an outwardly-opening trip-valve gate 11. This valve'is suitably pivoted upon the spout and has upon the outside of said spout a weighted arm or lever 12, by means of which the valve is overbalanced and normally held in position to close the spout. the upper portion of the said outer casing is an air-inlet pipe 13, which leads into the air space or chamber 7 and is preferably provided with a valve 14:.

Within the upper portion of the casing 1 and above the perforated lower portion thereof is a hood or spreader 15,which is here shown as a plate of conical form, with its apex below and in line with the inlet-spout 3, and an eduction-pipe 16 leads from the inner side of this plate below its apex to the eye of a suitable exhaust-fan 17.

Such being the construction of the present apparatus, its operation is now to be considered. The valve 11 being in its normal closed position and the valve 14 being opened to permit a current of air of desired volume to be drawn through the apparatus by the fan 17, the pulverized material (or other material to be acted upon) is fed to the casing through the spout 3 and falls upon the spreader by which said material is spread and caused to fall from the spreader near the inner wall of the perforated casing in a relatively thin sheet. The current of air which is being drawn inwardly through the perforations 5 and toward the apex of the spreader meets this thin sheet of material,and thus intimately engages the particles thereof, the particles of suificient fineness being delivered by the air to the fan 17 and being then discharged to any suitable or desired point. Those particles of the material too heavy to be supported by the said air-current fall through the discharge-opening 6 and upon thegate 11, by which they are supported,until a sufficient mass has accumulated to trip said gate, when the gate opens and discharges the tailings into the spout 10. Manifestly the fineness of the product delivered to the fan depends upon the volume of the air-current, and such volume is regulated by the valve 14, the valve 11 normally closing the spout or pipe 10 and the weighting of said valve 11, as previously described, insuring the holding of said valve in closed position until such an amount of tailings has collected thereon that when they are discharged by the tripping of the valve they substantially fill the spout 10, and thus permit no air to be drawn therethrough even when the valve is open for discharging the tailings.

The present apparatus is simple and cheap in its construction and most efficiently performs its work. The material to be acted upon is fed to the air-current in the best manner for effecting the desired separation, the air iscaused to intimately commingle with said material,.the current of air can be regulated to the greatest nicety, and the tailings are discharged in a manner which does not interfere with the regulation of the air-current.

We are aware that many minor changes in the construction, arrangement, and combination of the several parts of our device can be made and substituted for those herein shown and described without'in the least departing from the nature and principle of our invention.

Having thus described our invention, What we claim as new, and desire to secure by Letters Patent, is

1. In an apparatus of the character indicated, the combination with a casing comprising a surrounding wall, a top wall spanning the space inclosed by said surrounding wall and provided with an inlet-opening for the material to be acted upon, and a perforated, inverted pyramidal portion having its upper portion connected to said surrounding wall and its lower end provided with a dischargeopening, of a pyramidal spreader in said casing with its bottom above said perforated portion and its apex below and in line with said inlet-opening for the material, an imperforate, inverted pyramidal casing-wall about said perforated portion and spaced therefrom to produce an air-space, said imperforate wall having a discharge-opening at its lower end and said opening at the lower end of said perforated portion discharging into said air-space, an overbalanced valve closing said opening at the lower end of said imperforate wall, means for closing the upper end of said air-space above said perforated portion, an air-inlet leading from atmosphere directly to said air-space, and an eduction-pipe leading from the interior of said pyramidal spreader to a point outside of the apparatus; substantially as described.

2. In an apparatus of the character indicated, a casing having a perforated, downwardly-tapering portion provided with a discharge-opening at its lower end, an upwardlytapering spreader above said perforated casing portion, an eduction opening leading from a point between the inclined walls of said spreader to a point outside of the hereinrecited casings, an outer casing about the said perforated, downwardly-tapering portion of said first-mentioned casing and spaced therefrom to produce an air-space, said first-mentioned casing discharging into said air-space, and an air-inlet leading directly to said airspace from a point outside of said casings; substantially as described.

3. In an apparatus of the character indicated, an outer casing, an inner, perforated casing spaced from said outer casing to produce an air-space and having a dischargeopening delivering from said inner easing into said space intermediate said casings, a wall closing the upper portion of the space between said casings to prevent passage of material from said inner casing to said air-space except through said discharge opening of said inner casing, an air-eductiou pipe leading from said inner casing to a point outside of said casings, and an air-inlet leading from a point outside of said casings directly to said space intermediate said casings, said air-inlet excluding said inner casing, whereby incoming air first enters said space intermediate said casings and then passes into said inner casing and to said eduction-pipe; substantially as described.

4. In an apparatus of the character described, the combination with a casing having an inlet through the top for material, of a pyramidal hood beneath said opening for spreading the material, a pipe connecting said hood with the eye of a suction-fan, and a perforated inverted pyramidal casing portion open at the bottom and connected to the body portion of said casing beneath said hood, with an air-space surrounding said pyramidal casing portion; substantially as described.

5. In an apparatus of the character indicated, a spreader having downwardly and outwardly inclined walls, a casing-wall about said spreader and extending above the same, a top casing-plate connecting said wall at its upper end and above said spreader, said cas- -ing being provided with an inlet-opening above said spreader, downwardly and in- IIO wardly inclined foraminous Walls connected In testimony whereof We have signed our to the lower end of said wail about said names to this specification in the presence of [O spreader and adapted to receive material detwo subscribing Witnesses.

livered from said spreader, an outer casing WILLIAM S. OSBORNE.

5 spaced from said foranlinous Walls to pro- ELWIN O. BRYANT.

duce an air-space, and asuction-opening Witnesses: leading from the interior of said spreader; JAMES B. MILLER,

suhsta'ntially as described. G. W. OSBORNE. 

